1,031 research outputs found
Evaluation of the rigid stable techniques of the sagittal split ramus osteotomies : mechanical, photoelastic, finite elements analysis and clinical stability studies
Orientadores: Márcio de Moraes, Luciana AsprinoTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: O objetivo nesse trabalho foi avaliar a resistência mecânica, a distribuição de tensões e a estabilidade em longo prazo das diversas formas de fixação da osteotomia sagital dos ramos mandibulares (OSRM). No trabalho 1, cinco técnicas de fixação da OSRM foram submetidas a análise de elementos finitos: 3 parafusos bicorticais lineares a 60° e a 90°, 3 parafusos bicorticais em disposição L invertido, 1 miniplaca com 4 parafusos monocorticais convencionais e com sistema de travamento. Pelos resultados obtidos, a disposição em L invertido foi a que apresentou melhor distribuição de tensões, seguido pela linear 90° e 60°. Em relação às miniplacas, as tensões apresentaram melhor distribuição naquela com sistema de travamento se comparada com a convencional. No trabalho 2, foi realizada um análise mecânica, fotoelástica e de elementos finitos da chamada técnica híbrida, comparando-a com a fixação tradicional com três parafusos bicorticais em L invertido e com miniplaca e parafusos monocorticais. A técnica híbrida apresentou resistência intermediária entre os dois sistemas tradicionais de fixação da OSRM, com concentração de tensões principalmente ao redor do parafuso bicortical e melhora da distribuição de tensões na região da miniplaca. No trabalho 3, foi realizada uma análise da estabilidade esquelética de três formas de fixação da OSRM: técnica híbrida, parafusos bicorticais e miniplacas/parafusos monocorticais. Os resultados mostraram não haver diferença estatisticamente significante entre os três grupos, sendo positiva a correlação entre a quantidade de avanço mandibular e a quantidade de recidiva. Pelos resultados obtidos nos trabalhos, pode-se concluir que todas as técnicas avaliadas podem ser empregadas com segurança na fixação da osteomia sagital dos ramos mandibularesAbstract: The aim of this research was to evaluate the mechanical resistance, stress distribution and long-term stability of fixation techniques of the sagittal split ramus osteotomy (SSRO). In the first study, five fixation techniques of the SSRO were submitted to finite element analysis: 3 linear screws 90°, 3 linear screws 60°, 3 screws in inverted L arrangement, conventional and locking miniplate with monocortical screws. The results demonstrated that the bicortical screws in inverted L arrangement presented the best stress distribution, followed by linear 90° and linear 60°. The locking system miniplate presented better stress distribution if compared with conventional miniplate and monocortical screws. In the second study, a mechanical, photoelastic and finite element analysis were performed to the so-called hybrid technique, comparing it with bicortical screws in inverted L arrangement and miniplate with monocortical screws. The hybrid technique had an intermediate mechanical resistance between the two traditional fixation techniques, with high stress concentration around the bicortical screw with improvement in the stress distribution around the miniplate. In the third study, skeletal stability was evaluated of three fixation techniques of the SSRO: the hybrid technique, bicortical screws and miniplates with monocortical screws. The results demonstrated no significant statistically difference between the groups, with a positive correlation between the amount of advancement and relapse. From the results obtained in the research, it is possible to conclude that all fixation techniques could be safely applied to sagital split ramus osteotomyDoutoradoCirurgia e Traumatologia Buco-Maxilo-FaciaisDoutor em Clínica Odontológic
Discriminating different classes of biological networks by analyzing the graphs spectra distribution
The brain's structural and functional systems, protein-protein interaction,
and gene networks are examples of biological systems that share some features
of complex networks, such as highly connected nodes, modularity, and
small-world topology. Recent studies indicate that some pathologies present
topological network alterations relative to norms seen in the general
population. Therefore, methods to discriminate the processes that generate the
different classes of networks (e.g., normal and disease) might be crucial for
the diagnosis, prognosis, and treatment of the disease. It is known that
several topological properties of a network (graph) can be described by the
distribution of the spectrum of its adjacency matrix. Moreover, large networks
generated by the same random process have the same spectrum distribution,
allowing us to use it as a "fingerprint". Based on this relationship, we
introduce and propose the entropy of a graph spectrum to measure the
"uncertainty" of a random graph and the Kullback-Leibler and Jensen-Shannon
divergences between graph spectra to compare networks. We also introduce
general methods for model selection and network model parameter estimation, as
well as a statistical procedure to test the nullity of divergence between two
classes of complex networks. Finally, we demonstrate the usefulness of the
proposed methods by applying them on (1) protein-protein interaction networks
of different species and (2) on networks derived from children diagnosed with
Attention Deficit Hyperactivity Disorder (ADHD) and typically developing
children. We conclude that scale-free networks best describe all the
protein-protein interactions. Also, we show that our proposed measures
succeeded in the identification of topological changes in the network while
other commonly used measures (number of edges, clustering coefficient, average
path length) failed
Multi-Instantons and Multi-Cuts
We discuss various aspects of multi-instanton configurations in generic
multi-cut matrix models. Explicit formulae are presented in the two-cut case
and, in particular, we obtain general formulae for multi-instanton amplitudes
in the one-cut matrix model case as a degeneration of the two-cut case. These
formulae show that the instanton gas is ultra-dilute, due to the repulsion
among the matrix model eigenvalues. We exemplify and test our general results
in the cubic matrix model, where multi-instanton amplitudes can be also
computed with orthogonal polynomials. As an application, we derive general
expressions for multi-instanton contributions in two-dimensional quantum
gravity, verifying them by computing the instanton corrections to the string
equation. The resulting amplitudes can be interpreted as regularized partition
functions for multiple ZZ-branes, which take into full account their
back-reaction on the target geometry. Finally, we also derive structural
properties of the trans-series solution to the Painleve I equation.Comment: 34 pages, 3 figures, JHEP3.cls; v2: added references, minor changes;
v3: added 1 reference, more minor changes, final version for JMP; v4: more
typos correcte
On the Implementation of the Probabilistic Logic Programming Language ProbLog
The past few years have seen a surge of interest in the field of
probabilistic logic learning and statistical relational learning. In this
endeavor, many probabilistic logics have been developed. ProbLog is a recent
probabilistic extension of Prolog motivated by the mining of large biological
networks. In ProbLog, facts can be labeled with probabilities. These facts are
treated as mutually independent random variables that indicate whether these
facts belong to a randomly sampled program. Different kinds of queries can be
posed to ProbLog programs. We introduce algorithms that allow the efficient
execution of these queries, discuss their implementation on top of the
YAP-Prolog system, and evaluate their performance in the context of large
networks of biological entities.Comment: 28 pages; To appear in Theory and Practice of Logic Programming
(TPLP
Tonsil fibromatosis
UNIFESP-EPM Departamento de Otorrinolaringologia e Cirurgia de Cabeça e PescoçoUNIFESP-EPM Clínica de Otorrinolaringologia PediátricaUNIFESP, EPM, Depto. de Otorrinolaringologia e Cirurgia de Cabeça e PescoçoUNIFESP, EPM Clínica de Otorrinolaringologia PediátricaSciEL
Abnormal Brain Connectivity Patterns in Adults with ADHD: A Coherence Study
Studies based on functional magnetic resonance imaging (fMRI) during the resting state have shown decreased functional connectivity between the dorsal anterior cingulate cortex (dACC) and regions of the Default Mode Network (DMN) in adult patients with Attention-Deficit/Hyperactivity Disorder (ADHD) relative to subjects with typical development (TD). Most studies used Pearson correlation coefficients among the BOLD signals from different brain regions to quantify functional connectivity. Since the Pearson correlation analysis only provides a limited description of functional connectivity, we investigated functional connectivity between the dACC and the posterior cingulate cortex (PCC) in three groups (adult patients with ADHD, n = 21; TD age-matched subjects, n = 21; young TD subjects, n = 21) using a more comprehensive analytical approach - unsupervised machine learning using a one-class support vector machine (OC-SVM) that quantifies an abnormality index for each individual. the median abnormality index for patients with ADHD was greater than for TD age-matched subjects (p = 0.014); the ADHD and young TD indices did not differ significantly (p = 0.480); the median abnormality index of young TD was greater than that of TD age-matched subjects (p = 0.016). Low frequencies below 0.05 Hz and around 0.20 Hz were the most relevant for discriminating between ADHD patients and TD age-matched controls and between the older and younger TD subjects. in addition, we validated our approach using the fMRI data of children publicly released by the ADHD-200 Competition, obtaining similar results. Our findings suggest that the abnormal coherence patterns observed in patients with ADHD in this study resemble the patterns observed in young typically developing subjects, which reinforces the hypothesis that ADHD is associated with brain maturation deficits.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)National Institute of Mental HealthNovartisJanssen-CilagAbbottEli-LillyShireBristol-Myers SquibbUniv Fed ABC, Ctr Math Computat & Cognit, Santo Andre, BrazilUniversidade Federal de São Paulo, Lab Interdisciplinar Neurociencias Clin, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Psychiat, São Paulo, BrazilHosp Clin Porto Alegre, Child & Adolescent Psychiat Div, ADHD Outpatient Program, Porto Alegre, RS, BrazilNYU, Ctr Child Study, Phyllis Green & Randolph Cowen Inst Pediat Neuros, New York, NY USAInst Nacl Psiquiatria Desenvolvimento, Porto Alegre, RS, BrazilUniversidade Federal de São Paulo, Lab Interdisciplinar Neurociencias Clin, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Psychiat, São Paulo, BrazilNational Institute of Mental Health: R01MH083246Web of Scienc
Prevalencia de anemia en embarazadas y la fortificación de harinas con hierro
Avaliou-se o impacto da fortificação das farinhas com ferro, na prevalência de anemia e concentração de hemoglobina de gestantes. Este estudo transversal retrospectivo foi desenvolvido em um Centro de Saúde Escola do município de São Paulo - SP. Os dados, colhidos de setembro a dezembro de 2006, foram obtidos de 750 prontuários de gestantes distribuídas em dois grupos (não fortificado e fortificado), antes e após a fortificação. Gestantes com nível de hemoglobina inferior a 11g/dl foram consideradas anêmicas. Realizou-se análise de regressão linear múltipla. A anemia afetava 9,2% e 8,6% das gestantes, antes e após a implantação do programa, respectivamente (p>0,05). A análise múltipla não evidenciou diferença estatística na média de hemoglobina entre os grupos (p=0,117). Os resultados indicaram uma baixa prevalência de anemia e médias de hemoglobina similares entre os grupos, fato que provavelmente não permitiu constatar o efeito da fortificação das farinhas.This study evaluated the impact of iron-fortified flours in the prevalence of anemia and hemoglobin levels of pregnant women. This transversal cross-sectional study was developed at a Health Center School in São Paulo - SP, Brazil. Data, collected from September to December of 2006, were obtained from 750 pregnant women's medical records and discriminated into two groups, before and after fortification: non-fortified and fortified. Pregnant women with hemoglobin levels lower than 11g/dl were considered anemic. Data were submitted to multiple regression analysis. Anemia affected 9.2% and 8.6% of pregnant women, before and after the fortification, respectively (p>0.05). Multiple analysis indicates no statistical difference in the mean hemoglobin levels between the groups (p=0.117). The results indicated a low prevalence of anemia and similar hemoglobin levels between the groups, which probably did not allow for demonstrating the effect of flour fortification.Se evaluó el impacto de la fortificación de harinas con hierro en la prevalencia de anemia y concentración de hemoglobina de gestantes. Este estudio transversal retrospectivo fue desarrollado en un Centro de Salud Escuela, de la ciudad de São Paulo - SP. Los datos, recogidos de septiembre a diciembre de 2006, fueron obtenidos de 750 manuales de gestantes, distribuidas en dos grupos, antes y después del inicio de la fortificación: no fortificado y fortificado. Las gestantes con nivel de hemoglobina inferior 11g/dl fueron consideradas anémicas. Se realizó el análisis de la regresión múltiple. La anemia afectó 9,2% y 8,6% de las gestantes, antes y después de la implantación del programa, respectivamente (p>0,05). El análisis de la regresión múltiple no evidenció diferencia estadística en el promedio de hemoglobina entre los grupos (p=0,117). Los resultados indicaron baja prevalencia de anemia y promedios similares de hemoglobina entre los grupos estudiados, hecho que probablemente no permitió demostrar el efecto de la fortificación de las harinas
Nasotracheal tube wire support: a safety device in maxillofacial surgery technical note after five years of experience
A well fixed endotracheal tube is essential for safety during general anesthesia. In maxillofacial surgeries, securely fixing a nasotracheal tube in place has always been problematic. The aim of this article is to describe a simple but effective technique to fasten the nasotracheal tube using a wire support that allows a full range of head movement without interference in the surgical field. During the last 5 years, this device was successfully used in almost two hundred patients with very few complications
Abnormal brain connectivity patterns in adults with ADHD : a coherence study
Studies based on functional magnetic resonance imaging (fMRI) during the resting state have shown decreased functional connectivity between the dorsal anterior cingulate cortex (dACC) and regions of the Default Mode Network (DMN) in adult patients with Attention-Deficit/Hyperactivity Disorder (ADHD) relative to subjects with typical development (TD). Most studies used Pearson correlation coefficients among the BOLD signals from different brain regions to quantify functional connectivity. Since the Pearson correlation analysis only provides a limited description of functional connectivity, we investigated functional connectivity between the dACC and the posterior cingulate cortex (PCC) in three groups (adult patients with ADHD, n = 21; TD age-matched subjects, n = 21; young TD subjects, n = 21) using a more comprehensive analytical approach – unsupervised machine learning using a one-class support vector machine (OC-SVM) that quantifies an abnormality index for each individual. The median abnormality index for patients with ADHD was greater than for TD agematched subjects (p = 0.014); the ADHD and young TD indices did not differ significantly (p = 0.480); the median abnormality index of young TD was greater than that of TD age-matched subjects (p = 0.016). Low frequencies below 0.05 Hz and around 0.20 Hz were the most relevant for discriminating between ADHD patients and TD age-matched controls and between the older and younger TD subjects. In addition, we validated our approach using the fMRI data of children publicly released by the ADHD-200 Competition, obtaining similar results. Our findings suggest that the abnormal coherence patterns observed in patients with ADHD in this study resemble the patterns observed in young typically developing subjects, which reinforces the hypothesis that ADHD is associated with brain maturation deficits
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